Detection of two different papillomaviruses within a feline cutaneous squamous cell carcinoma: case report and review of the literature.

CASE HISTORY: A 15-year-old, brown-and-white cat was presented to a veterinary clinic with an ulcerated, reddened 1-cm diameter lesion on the nasal planum. CLINICAL FINDINGS AND DIAGNOSIS: Histology of a biopsy sample confirmed the lesion was a squamous cell carcinoma (SCC). PCR amplified DNA sequences from two different papillomaviruses. One sequence was from FdPV-2, which has previously been amplified from feline cutaneous SCC. However, the other sequence has not previously been reported, suggesting a novel feline papillomavirus. CLINICAL RELEVANCE: There is evidence that papillomaviruses promote the development of SCC on sun-exposed skin in humans. This is the first report in a cat of a papillomavirus other than FdPV-2 and the first time that multiple papillomaviruses have been detected within a single neoplasm in this species. Whether the papillomaviruses influenced the development and behaviour of this SCC is currently uncertain, but this case provides additional evidence of the association between papillomaviruses and feline cutaneous SCC. If papillomaviruses are found to influence the development of SCC this may allow novel strategies to prevent these common neoplasms in cats.